The armed forces said in a statement "a group of civilian criminals wearing military uniforms and a first lieutenant who had deserted" carried out the attack on a base in the city of Valencia.

A still image from video released by Operation David Carabobo purportedly shows a group of men dressed in military uniforms announcing uprising in Valencia.

Venezuela's military was hunting a group of "mercenaries" on Monday who made off with weapons after an attack on an army base carried out against what they called the "murderous tyranny" of President Nicolas Maduro.

Around 20 men led by an army officer who had deserted battled troops in the base in the third-largeset city of Valencia for three hours early Sunday, officials said.

The raid ended with two of the attackers being killed and eight captured, Maduro said on state television.

The other 10 escaped with weapons taken from the facility, according to officials who said an "intense search" was underway for them. The officials added that several of the "terrorists" had been arrested and insisted all was normal across the country.

TRT World'sStaci Bivens reports.

Locals said a nighttime curfew had been imposed, as flaming barricades set up in the street by anti-government protesters spewed black smoke.

The incident heightened fears that Venezuela's deepening political and economic crisis could explode into greater violence, perhaps open armed conflict.

The armed forces said in a statement "a group of civilian criminals wearing military uniforms and a first lieutenant who had deserted" carried out the attack, during which a number of weapons were stolen.

"Terrorists from Miami and Colombia"

​The statement said those detained had "confessed" to being hired by "extreme-right activists, in connection with foreign governments."

It did not identify those governments.

But President Maduro said on state television they were "terrorists from Miami and Colombia."

Maduro congratulated the army for its "immediate reaction" in putting down the attack.

Venezuela has become increasingly isolated internationally as Maduro has tightened his hold on power through a contested loyalist assembly that started work this week.

The opposition, which controls the legislature, has been sidelined. Its leaders are under threat of arrest after organising protests, fiercely countered by security forces, that have left 125 people dead in the past four months.

One prominent leader, Leopoldo Lopez, was returned to house arrest after being hauled off to military prison four days ago.

The new Constituent Assembly, packed with Maduro allies, including the president's wife and son, has quickly used its supreme powers to clamp down on dissent.

On Saturday, it ordered the dismissal of the attorney general, Luisa Ortega, who had broken ranks with Maduro to become one of his most vociferous critics.

On Sunday it announced – then suspended – the creation of a "truth commission" sought by Maduro to probe alleged crimes by the opposition.